Статті в журналах: "Double Multiple Streamtubes"

1

Paraschivoiu, Ion. "Double-multiple streamtube model for studying vertical-axis wind turbines." Journal of Propulsion and Power 4, no. 4 (July 1988): 370–77. http://dx.doi.org/10.2514/3.23076.

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2

Roy, Lalit, Kellis Kincaid, Roohany Mahmud, and David W. MacPhee. "Double-Multiple Streamtube Analysis of a Flexible Vertical Axis Wind Turbine." Fluids 6, no. 3 (March 13, 2021): 118. http://dx.doi.org/10.3390/fluids6030118.

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Vertical-axis wind turbines (VAWTs) have drawn increased attention for off-grid and off-shore power generation due to inherent advantages over the more popular horizontal-axis wind turbines (HAWTs). Among these advantages are generator locale, omni-directionality and simplistic design. However, one major disadvantage is lower efficiency, which can be alleviated through blade pitching. Since each blade must transit both up- and down-stream each revolution, VAWT blade pitching techniques are not yet commonplace due to increased complexity and cost. Utilizing passively-morphing flexible blades can offer similar results as active pitching, requiring no sensors or actuators, and has shown promise in increasing VAWT performance in select cases. In this study, wind tunnel tests have been conducted with flexible and rigid-bladed NACA 0012 airfoils, in order to provide necessary input data for a Double-Multiple Stream-Tube (DMST) model. The results from this study indicate that a passively-morphing VAWT can achieve a maximum power coefficient (Cp) far exceeding that for a rigid-bladed VAWT CP (18.9% vs. 10%) with reduced normal force fluctuations as much as 6.9%. Operational range of tip-speed ratio also is observed to increase by a maximum of 40.3%.

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3

Saber, E., R. Afify, and H. Elgamal. "Performance of SB-VAWT using a modified double multiple streamtube model." Alexandria Engineering Journal 57, no. 4 (December 2018): 3099–110. http://dx.doi.org/10.1016/j.aej.2018.07.009.

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4

Beri, Habtamu, and Yingxue Yao. "Double Multiple Streamtube Model and Numerical Analysis of Vertical Axis Wind Turbine." Energy and Power Engineering 03, no. 03 (2011): 262–70. http://dx.doi.org/10.4236/epe.2011.33033.

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5

Kumar, Palanisamy Mohan, Sudhakar Rao Rashmitha, Narasimalu Srikanth, and Teik-Cheng Lim. "Wind Tunnel Validation of Double Multiple Streamtube Model for Vertical Axis Wind Turbine." Smart Grid and Renewable Energy 08, no. 12 (2017): 412–24. http://dx.doi.org/10.4236/sgre.2017.812027.

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6

Bangga, Galih, Amgad Dessoky, Thorsten Lutz, and Ewald Krämer. "Improved double-multiple-streamtube approach for H-Darrieus vertical axis wind turbine computations." Energy 182 (September 2019): 673–88. http://dx.doi.org/10.1016/j.energy.2019.06.083.

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7

Cacciali, L., L. Battisti, and S. Dell’Anna. "Free Surface Double Actuator Disc Theory and Double Multiple Streamtube model for in-stream Darrieus hydrokinetic turbines." Ocean Engineering 260 (September 2022): 112017. http://dx.doi.org/10.1016/j.oceaneng.2022.112017.

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8

Hara, Yutaka, Takafumi Kawamura, Hiromichi Akimoto, Kenji Tanaka, Takuju Nakamura, and Kentaro Mizumukai. "Predicting Double-Blade Vertical Axis Wind Turbine Performance by a Quadruple-Multiple Streamtube Model." International Journal of Fluid Machinery and Systems 7, no. 1 (March 31, 2014): 16–27. http://dx.doi.org/10.5293/ijfms.2014.7.1.016.

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9

Ayati, Anis A., Konstantinos Steiros, Mark A. Miller, Subrahmanyam Duvvuri, and Marcus Hultmark. "A double-multiple streamtube model for vertical axis wind turbines of arbitrary rotor loading." Wind Energy Science 4, no. 4 (December 11, 2019): 653–62. http://dx.doi.org/10.5194/wes-4-653-2019.

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Abstract. We introduce an improved formulation of the double-multiple streamtube (DMST) model for the prediction of the flow quantities of vertical axis wind turbines (VAWT). The improvement of the new formulation lies in that it renders the DMST valid for any induction factor, i.e., for any combination of rotor solidity and tip speed ratio. This is done by replacing the Rankine–Froude momentum theory of the DMST, which is invalid for moderate and high induction factors, with a new momentum theory recently proposed, which provides sensible results for any induction factor. The predictions of the two DMST formulations are compared with VAWT power measurements obtained at Princeton's High Reynolds number Test Facility, over a range of tip speed ratios, rotor solidities, and Reynolds numbers, including those experienced by full-scale turbines. The results show that the new DMST formulation demonstrates a better overall performance, compared to the conventional one, when the rotor loading is moderate or high.

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10

Dyachuk, Eduard, and Anders Goude. "Simulating Dynamic Stall Effects for Vertical Axis Wind Turbines Applying a Double Multiple Streamtube Model." Energies 8, no. 2 (February 11, 2015): 1353–72. http://dx.doi.org/10.3390/en8021353.

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11

Wendler, Richard, Williams R. Calderón-Muñoz, and Richard LeBoeuf. "Energy-based iteration scheme of the double-multiple streamtube model in vertical-axis wind turbines." Acta Mechanica 227, no. 11 (January 23, 2016): 3295–303. http://dx.doi.org/10.1007/s00707-015-1544-7.

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12

Morgan, Laurence, and William Leithead. "Aerodynamic modelling of a novel vertical axis wind turbine concept." Journal of Physics: Conference Series 2257, no. 1 (April 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2257/1/012001.

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Abstract This paper introduces the X-Rotor, a hybrid vertical-horizontal axis turbine concept designed to lower the cost of energy in the floating offshore environment. The development of a double multiple streamtube (DMS) simulation tool is presented alongside a thorough discussion of the secondary correction factors included in the model. New corrections for streamline curvature effects applicable to an airfoil where the blade normal plane is not aligned with the rotor plane are derived. The DMS model is successfully validated against experimental data and against higher fidelity lifting line (LLT) simulations. Strong agreement is observed between the LLT simulations and the DMS simulations for both rotor averaged and azimuthally varying outputs, indicating that the DMS simulations can be used for future control simulations.

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13

Yang, Rui, Jin Long Li, Wei Wei Xia, and Ting Ting Wang. "Rotor Design and Performance Study of a Vertical-Axis Wind Turbine Based on DMS." Applied Mechanics and Materials 448-453 (October 2013): 1892–96. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.1892.

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Specifically address the design of a 5KW H-type vertical-axis wind turbine (H-VAWT) with NACA 0018 airfoil considering the factors that affect wind turbine power. The double-multiple streamtube (DMS) theoretical model is analyzed and summarized and calculated by Matlab. The 5KW H-type vertical axis wind turbines aerodynamic performance is calculated by the model written in Matlab. The curve of the power coefficient as a function of the tip-speed ratio and the curve of the normal force coefficient and the tangential farce as a function of the blade position is given by Matlab. From the curves we can see that upwind rotor aerodynamic load is larger, downwind rotor aerodynamic load is smaller and there is a serious flow retarding effect in the rotor downwind area.

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14

Tchakoua, Pierre, René Wamkeue, Mohand Ouhrouche, Ernesto Benini, and Gabriel Ekemb. "Electric Circuit Model for the Aerodynamic Performance Analysis of a Three-Blade Darrieus-Type Vertical Axis Wind Turbine: The Tchakoua Model." Energies 9, no. 10 (October 14, 2016): 820. http://dx.doi.org/10.3390/en9100820.

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The complex and unsteady aerodynamics of vertical axis wind turbines (VAWTs) pose significant challenges for simulation tools. Recently, significant research efforts have focused on the development of new methods for analysing and optimising the aerodynamic performance of VAWTs. This paper presents an electric circuit model for Darrieus-type vertical axis wind turbine (DT-VAWT) rotors. The novel Tchakoua model is based on the mechanical description given by the Paraschivoiu double-multiple streamtube model using a mechanical‑electrical analogy. Model simulations were conducted using MATLAB for a three-bladed rotor architecture, characterized by a NACA0012 profile, an average Reynolds number of 40,000 for the blade and a tip speed ratio of 5. The results obtained show strong agreement with findings from both aerodynamic and computational fluid dynamics (CFD) models in the literature.

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15

Meana-Fernández, Andrés, Jesús Manuel Fernández Oro, Katia María Argüelles Díaz, Mónica Galdo-Vega, and Sandra Velarde-Suárez. "Aerodynamic Design of a Small-Scale Model of a Vertical Axis Wind Turbine." Proceedings 2, no. 23 (November 1, 2018): 1465. http://dx.doi.org/10.3390/proceedings2231465.

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Wind tunnel testing of small-scale models is one of the most useful techniques to predict the performance of real-scale applications. In this work, the aerodynamic design and the construction of a small-scale model of a straight-bladed vertical axis wind turbine for wind tunnel testing has been performed. Using a double multiple streamtube model (DMST), different solidity values for the turbine and different airfoil geometries were compared to select the final design. Once an optimal design was selected, a numerical simulation using Computational Fluid Dynamics (CFD) was performed in order to obtain a more precise description of the flow field as well as the performance of the model. Future work will comprise the characterization of the model and the comparison of the experimental and numerical results.

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16

Batista, Nelson, Rui Melicio, and Victor Mendes. "Darrieus-type vertical axis rotary-wings with a new design approach grounded in double-multiple streamtube performance prediction model." AIMS Energy 6, no. 5 (2018): 673–94. http://dx.doi.org/10.3934/energy.2018.5.673.

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17

Batista, Nelson, Rui Melicio, and Victor Mendes. "Darrieus-type vertical axis rotary-wings with a new design approach grounded in double-multiple streamtube performance prediction model." AIMS Energy 6, no. 5 (2018): 673–94. http://dx.doi.org/10.3934/energy.2018.5.673.

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18

Kirke, Brian K., and Benoit Paillard. "Predicted and measured performance of a vertical axis wind turbine with passive variable pitch compared to fixed pitch." Wind Engineering 41, no. 1 (November 15, 2016): 74–90. http://dx.doi.org/10.1177/0309524x16677884.

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The performance of a 5-m diameter Darrieus vertical axis wind turbine was predicted using both a double multiple streamtube model and a two-dimensional unsteady Reynolds-averaged Navier–Stokes computational fluid dynamics simulation with constant rotational speed for a series of operational points. The actual performance was measured in both fixed and variable pitch modes. The aims were (1) to compare starting torque and peak efficiency in fixed and variable pitch modes and (2) to test an overspeed control mechanism. Starting torque was approximately three times higher in variable pitch mode and the maximum efficiency on some runs was significantly higher. The overspeed control mechanism functioned consistently as designed. Thus, variable pitch was shown to overcome two major disadvantages of normal fixed pitch vertical axis wind turbines, self-starting and overspeed control. Discrepancies between the predicted and measured results showed the importance of accurately assessing parasitic drag losses and the need for three-dimensional simulation to give reliable performance predictions.

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19

Paraschivoiu, I., O. Trifu, and F. Saeed. "H-Darrieus Wind Turbine with Blade Pitch Control." International Journal of Rotating Machinery 2009 (2009): 1–7. http://dx.doi.org/10.1155/2009/505343.

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A procedure for computing the optimal variation of the blades' pitch angle of an H-Darrieus wind turbine that maximizes its torque at given operational conditions is proposed and presented along with the results obtained on a 7 kW prototype. The CARDAAV code, based on the “Double-Multiple Streamtube” model developed by the first author, is used to determine the performances of the straight-bladed vertical axis wind turbine. This was coupled with a genetic algorithm optimizer. The azimuthal variation of the blades' pitch angle is modeled with an analytical function whose coefficients are used as variables in the optimization process. Two types of variations were considered for the pitch angle: a simple sinusoidal one and one which is more general, relating closely the blades' pitch to the local flow conditions along their circular path. A gain of almost 30% in the annual energy production was obtained with the polynomial optimal pitch control.

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20

Homicz, Gregory F. "VAWT Stochastic Loads Produced by Atmospheric Turbulence." Journal of Solar Energy Engineering 111, no. 4 (November 1, 1989): 358–66. http://dx.doi.org/10.1115/1.3268335.

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Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). A principal source of blade fatigue is thought to be the stochastic (i.e., random) aerodynamic loads created by atmospheric turbulence. This paper discusses the development of a model for the simulation of these stochastic loads, given the rotor geometry, operating conditions, and assumed turbulence properties. A Double-Multiple-Streamtube analysis is employed, which includes the effects of wind shear, Reynolds number variations, different airfoil sections and chord lengths along the blade span, and an empirical model for dynamic stall effects. Calculations are presented for the VAWT 34-m Test Bed recently erected at Bushland, Texas. Time histories of the loads, as well as their Fourier spectra, are presented and discussed. An unexpected finding is that the average output power is predicted to be more sensitive to turbulence level than had previously been thought.

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21

Masson, Christian, Christophe Leclerc, and Ion Paraschivoiu. "Appropriate Dynamic-Stall Models for Performance Predictions of VAWTs with NLF Blades." International Journal of Rotating Machinery 4, no. 2 (1998): 129–39. http://dx.doi.org/10.1155/s1023621x98000116.

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This paper illustrates the relative merits of using Natural Laminar Flow (NLF) airfoils in the design of Vertical Axis Wind Turbines (VAWT). This is achieved by the application of the double-multiple-streamtube model of Paraschivoiu to the performance predictions of VAWTs equipped with conventional and NLF blades. Furthermore, in order to clearly illustrate the potential benefit of reducing the drag, the individual contributions of lift and drag to power are presented. The dynamic-stall phenomena are modelled using the method of Gormont as modified by several researchers. Among the various implementations of this dynamic-stall model available in the literature, the most appropriate and general for NLF applications has been identified through detailed comparisons between predicted performances and experimental data. This selection process is presented in the paper. It has been demonstrated that the use ofNLF airfoils in VAWT applications can lead to significant improvements with respect to conventional design only in a very low wind speed range, the extent of which is negligible with respect to the VAWT operational wind speeds.

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22

Laín, Santiago, Pablo Cortés, and Omar Darío López. "Numerical Simulation of the Flow around a Straight Blade Darrieus Water Turbine." Energies 13, no. 5 (March 3, 2020): 1137. http://dx.doi.org/10.3390/en13051137.

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In this study, three-dimensional transient numerical simulations of the flow around a cross flow water turbine of the type H-Darrieus are performed. The hydrodynamic characteristics and performance of the turbine are investigated by means of a time-accurate unsteady Reynolds-averaged Navier–Stokes (URANS) commercial solver (ANSYS-Fluent v. 19) where the time dependent rotor-stator interaction is described by the sliding mesh approach. The transition shear stress transport turbulence model has been employed to represent the turbulent dynamics of the underlying flow. Computations are validated versus previous experimental work in terms of the turbine efficiency curve showing good agreement between numerical and experimental values. The behavior of the power and force coefficients as a function of turbine angular speed is analyzed. Moreover, visualizations and analyses of the instantaneous vorticity iso-surfaces developing at different blade rotational velocities are presented including a few movies as additional material. Finally, the fluid variables fields are averaged along a turbine revolution and are compared with the steady predictions of simplified steady approaches based on the blade element momentum theory and the double multiple streamtube method (BEM-DMS).

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23

Brahimi, M. T., and I. Paraschivoiu. "Darrieus Rotor Aerodynamics in Turbulent Wind." Journal of Solar Energy Engineering 117, no. 2 (May 1, 1995): 128–36. http://dx.doi.org/10.1115/1.2870839.

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The earlier aerodynamic models for studying vertical axis wind turbines (VAWT’s) are based on constant incident wind conditions and are thus capable of predicting only periodic variations in the loads. The purpose of the present study is to develop a mode capable of predicting the aerodynamic loads on the Darrieus rotor in a turbulent wind. This model is based on the double-multiple streamtube method (DMS) and incorporates a stochastic wind model The method used to simulate turbulent velocity fluctuations is based on the power spectral density. The problem consists in generating a region of turbulent flow with a relevant spectrum and spatial correlation. The first aerodynamic code developed is based on a one-dimensional turbulent wind model. However, since this model ignores the structure of the turbulence in the crossflow plane, an extension to three dimensions has been made. The computer code developed, CARDAAS, has been used to predict aerodynamic loads for the Sandia-17m rotor and compared to CARDAAV results and experimental data. Results have shown that the computed aerodynamic loads have been improved by including stochastic wind into the aerodynamic model.

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24

Allet, A., and I. Paraschivoiu. "Viscous Flow and Dynamic Stall Effects on Vertical-Axis Wind Turbines." International Journal of Rotating Machinery 2, no. 1 (1995): 1–14. http://dx.doi.org/10.1155/s1023621x95000157.

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The present paper describes a numerical method, aimed to simulate the flow field of vertical-axis wind turbines, based on the solution of the steady, incompressible, laminar Navier-Stokes equations in cylindrical coordinates. The flow equations, written in conservation law form, are discretized using a control volume approach on a staggered grid. The effect of the spinning blades is simulated by distributing a time-averaged source terms in the ring of control volumes that lie in the path of turbine blades. The numerical procedure used here, based on the control volume approach, is the widely known “SIMPLER” algorithm. The resulting algebraic equations are solved by the TriDiagonal Matrix Algorithm (TDMA) in the r- and z-directions and the Cyclic TDMA in the 0-direction. The indicial model is used to simulate the effect of dynamic stall at low tip-speed ratio values. The viscous model, developed here, is used to predict aerodynamic loads and performance for the Sandia 17-m wind turbine. Predictions of the viscous model are compared with both experimental data and results from the CARDAAV aerodynamic code based on the Double-Multiple Streamtube Model. According to the experimental results, the analysis of local and global performance predictions by the 3D viscous model including dynamic stall effects shows a good improvement with respect to previous 2D models.

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25

Cacciali, Luca, Lorenzo Battisti, and Sergio Dell’Anna. "Multi-Array Design for Hydrokinetic Turbines in Hydropower Canals." Energies 16, no. 5 (February 27, 2023): 2279. http://dx.doi.org/10.3390/en16052279.

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The design of hydrokinetic plants in hydropower canals involves the choice of the array layout, rotor geometry, turbine spacing, and array spacing, and necessitates the control of the resultant backwater to avoid upstream flooding hazards. Several works in the literature have shown that array power optimization is feasible with small spacings between the arrays, disregarding the limitation in the power output induced by backwater upstream. In this study, a 1-D channel model with a Double Multiple Streamtube code and wake sub-models are integrated to predict an array layout that will maximize the array power. The outputs of the conducted sensitivity analysis confirm that this design enabled improved power conversion with closely spaced turbines and largely spaced arrays, thus allowing for a partial recovery of the total head variation for a new array deployed upstream. In addition to the quantitative assessment of the mechanical power converted, the tool enables depth control from the downstream undisturbed flow station to the backwater exhaustion far upstream, thereby increasing its flexibility. Furthermore, it overcomes the limitations of actuator disc models by considering rotor’s fluid dynamic losses. The results show that power output linearly scales for a limited number of arrays (≤5), whilst the variation in water depth variation follows a power law from the most downstream array towards upstream, regardless of the plant size. Finally, the maximum upstream inflow depth is demonstrated to become asymptotic for large multi-array plants under ideal conditions.

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26

Rogowski, Krzysztof, Grzegorz Królak, and Galih Bangga. "Numerical Study on the Aerodynamic Characteristics of the NACA 0018 Airfoil at Low Reynolds Number for Darrieus Wind Turbines Using the Transition SST Model." Processes 9, no. 3 (March 7, 2021): 477. http://dx.doi.org/10.3390/pr9030477.

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A symmetrical NACA 0018 airfoil is often used in such applications as small-to-medium scale vertical-axis wind turbines and aerial vehicles. A review of the literature indicates a large gap in experimental studies of this airfoil at low and moderate Reynolds numbers in the previous century. This gap has limited the potential development of classical turbulence models, which in this range of Reynolds numbers predict the lift coefficients with insufficiently accurate results in comparison to contemporary experimental studies. Therefore, this paper validates the aerodynamic performance of the NACA 0018 airfoil and the characteristics of the laminar separation bubble formed on its suction side using the standard uncalibrated four-equation Transition SST turbulence model and the unsteady Reynolds-averaged Navier-Stokes (URANS) equations. A numerical study was conducted for the chord Reynolds number of 160,000, angles of attack between 0 and 11 degrees, as well as for the free-stream turbulence intensity of 0.05%. The calculated lift and drag coefficients, aerodynamic derivatives, as well as the location and length of the laminar bubble quite well agree with the results of experimental measurements taken from the literature for validation. A sensitivity study of the numerical model was performed in this paper to examine the effects of the time-step size, geometrical parameters and mesh distribution around the airfoil on the simulation results. The airfoil data sets obtained in this work using the Transition SST and the k-ω SST turbulence models were used in the improved double multiple streamtube (IDMS) to calculate aerodynamic blade loads of a vertical-axis wind turbine. The characteristics of the normal component of the aerodynamic blade load obtained by the Transition SST approach are much better suited to the experimental data compared to the k-ω SST turbulence model.

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27

Marten, David, Alessandro Bianchini, Georgios Pechlivanoglou, Francesco Balduzzi, Christian Navid Nayeri, Giovanni Ferrara, Christian Oliver Paschereit, and Lorenzo Ferrari. "Effects of Airfoil's Polar Data in the Stall Region on the Estimation of Darrieus Wind Turbine Performance." Journal of Engineering for Gas Turbines and Power 139, no. 2 (September 13, 2016). http://dx.doi.org/10.1115/1.4034326.

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Interest in vertical-axis wind turbines (VAWTs) is experiencing a renaissance after most major research projects came to a standstill in the mid 1990s, in favor of conventional horizontal-axis turbines (HAWTs). Nowadays, the inherent advantages of the VAWT concept, especially in the Darrieus configuration, may outweigh their disadvantages in specific applications, like the urban context or floating platforms. To enable these concepts further, efficient, accurate, and robust aerodynamic prediction tools and design guidelines are needed for VAWTs, for which low-order simulation methods have not reached yet a maturity comparable to that of the blade element momentum theory for HAWTs' applications. The two computationally efficient methods that are presently capable of capturing the unsteady aerodynamics of Darrieus turbines are the double multiple streamtubes (DMS) theory, based on momentum balances, and the lifting line theory (LLT) coupled to a free vortex wake model. Both methods make use of tabulated lift and drag coefficients to compute the blade forces. Since the incidence angles range experienced by a VAWT blade is much wider than that of a HAWT blade, the accuracy of polars in describing the stall region and the transition toward the “thin plate like” behavior has a large effect on simulation results. This paper will demonstrate the importance of stall and poststall data handling in the performance estimation of Darrieus VAWTs. Using validated CFD simulations as a baseline, comparisons are provided for a blade in VAWT-like motion based on a DMS and a LLT code employing three sets of poststall data obtained from a wind tunnel campaign, XFoil predictions extrapolated with the Viterna–Corrigan model and a combination of them. The polar extrapolation influence on quasi-steady operating conditions is shown and azimuthal variations of thrust and torque are compared for exemplary tip-speed ratios (TSRs). In addition, the major relevance of a proper dynamic stall model into both the simulation methods is highlighted and discussed.

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28

Mohammed, Amin A., Hassen M. Ouakad, Ahmet Z. Sahin, and Haitham M. S. Bahaidarah. "Vertical Axis Wind Turbine Aerodynamics: Summary and Review of Momentum Models." Journal of Energy Resources Technology 141, no. 5 (February 18, 2019). http://dx.doi.org/10.1115/1.4042643.

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Momentum models or streamtube models represent one of the fundamental approaches in modeling the aerodynamics of straight bladed vertical axis wind turbine (SB-VAWT) of Darrieus type. They are based on momentum (actuator disk) theory and widely used in performance evaluation of VAWTs. In this short review, the authors have strived to compile the basic momentum models that have been widely assumed in the literature for design and performance estimation of SB-VAWTs of Darrieus type. A comprehensive demonstration of the formulation needed for the implantation of these models is also proposed. Three streamtube models are investigated in this paper, namely, the single streamtube (SST), the multiple streamtube (MST), and the double multiple streamtube (DMST) models. Each of these models has it merits and demerits which are also thoroughly discussed in this review.

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29

Batista, N. C., R. Melício, J. C. O. Matias, and J. P. S. Catalão. "Vertical Axis Wind Turbine Performance Prediction: An Approach to the Double Multiple Streamtube Model." Renewable Energy and Power Quality Journal, April 2012, 633–36. http://dx.doi.org/10.24084/repqj10.410.

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30

Mohammed, Amin A., Ahmet Z. Sahin, and Hassen M. Ouakad. "Numerical Investigation of a Vertical Axis Wind Turbine Performance Characterization Using New Variable Pitch Control Scheme." Journal of Energy Resources Technology 142, no. 3 (November 26, 2019). http://dx.doi.org/10.1115/1.4045462.

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Abstract A double multiple streamtube model coupled with variable pitch methodology is used to analyze the performance characteristics of a small-scale straight-bladed Darrieus type vertical axis wind turbine (SB-VAWT). The numerical study revealed that a fixed pitch of −2.5 deg could greatly enhance the performance of the wind turbine. However, no improvement is observed in the starting torque capacity. Furthermore, the performance of upwind and downwind zones has been investigated, and it is found that the VAWT starting capacity is improved by increasing/decreasing the pitch angle upwind/downwind of the turbine. To optimize the performance, four cases of variable pitch angle schemes of sinusoidal nature were examined. The parameters of the sinusoidal functions were optimized using differential evolution (DE) algorithm with different cost functions. The results showed improvement in the power coefficient, yet with low starting capacity enhancement. Among the objective functions used in DE algorithm, the negative of the average power coefficient is found to lead to the best starting capacity with moderate peak power coefficient.

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31

Ahmad, Muhammad, Aamer Shahzad, Farooq Akram, and Muhammad Nafees Mumtaz Qadri. "Determination of efficient configurations of vertical axis wind turbine using design of experiments." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, April 27, 2022, 095765092210953. http://dx.doi.org/10.1177/09576509221095347.

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This study aims to optimize the design parameters of a vertical axis wind turbine using design of experiments (DOE). Response surface methodology combined with desirability optimization was used to optimize multiple parameters such as the chord length, number of blades, aspect ratio, and pitch angle. The range of contributing parameters was selected using one factor at a time (OFAT) approach, and the performance parameters were evaluated by applying the double multiple streamtube theory. Datasets retrieved from the Q-Blade open-source software were employed in the DOE to determine the optimal configurations. Based on response surface investigation, a quadratic model was established and the accuracy of the model was determined by applying analysis of variance, goodness of fit, normal plot of residuals, and R-squared values. The optimized chord length, number of blades, pitch angle, and aspect ratio were 0.546 m, 03, −2.82°, and 0.808, respectively. The maximum power coefficient of 0.45 was obtained at a tip speed ratio of 3 from the optimized design parameters. The analysis revealed an increase of approximately 8.43% in the maximum power coefficient of the proposed wind turbine. A 3D unsteady computational fluid dynamics model along with Reynolds-Averaged Navier-Stokes equations were utilized to verify the obtained results, and a maximum difference of less than 1.5% was found. A standard H-rotor Darrieus configuration obtained from the OFAT approach was also tested at different wind speeds for comparison. The analysis revealed that when the wind speed was less than 3.85 m/sec, the standard Darrieus produced no power; however, the self-starting speed of the optimized VAWT was as low as 3.22 m/sec. This novel design methodology provides guidelines for obtaining optimum design configurations and can help in achieving high-fidelity analysis in the early design phase.

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Ramkissoon, Rikhi, Krishpersad Manohar, and Anthony Adeyanju. "Wind Energy Production from Vertical Axis Wind Turbine on Offshore Production Platforms in Trinidad." Journal of Energy Research and Reviews, April 30, 2022, 38–47. http://dx.doi.org/10.9734/jenrr/2022/v11i130269.

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Aims: To estimate the available power that can be generated from wind on Oil and Gas production Platforms offshore Trinidad. Place and Duration of Study: Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, University of the West Indies, St Augustine Campus. Data collected at a bpTT production platform offshore east coast Trinidad between January 2019 to November 2019. Methodology: The East coast of Trinidad was chosen due to the presence of high yearly wind speeds. The wind data was collected 80 kilometers off Trinidad Southeast coast, east of the bpTT Cashima production platform for the year 2019. Wind speeds varied from 5.3 meters per second in October to 8.8 meters per second in June. The overall wind speed average for the year 2019 was 7.4 meters per second. The vertical axis wind turbine considered here was modeled using Parashivoiu's double multiple streamtube model concept. The VAWT modelled had 3 NACA0018 blade profile, a blade length of 2.5 meters and a diameter of 2 meters. Results: The modeled vertical axis wind turbine monthly total power output varied from 5.43 KW to 20.34 KW. The daily average expected power output from the VAWT ranged from 175 Watts to 678 Watts. It can be observed that the months January to July gave higher daily and monthly average power generation due to these months having the highest wind speeds due to local weather conditions. Conclusion: The VAWT modelled in this study can generate on average, 463 Watts of power per day with a peak average of 678 Watts of power per day in June from a single turbine. The total average power produced for the year 2019 was 151.11 KW. The turbine was sized as not to have a large footprint on the offshore platform. It is demonstrated here that substantial support and rationale is needed for the potential advancement of VAWT’s for conditions that prevail offshore Trinidad, owing to their lower extraction costs and more robust geometry due to the use of existing offshore platforms.

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